A similar control device is known, for example, from US 2007/0181410 A1. A signal generated by a signal generator beneath the support is capacitively transmitted to a conductive sensor surface on the underside of the control element. Said sensor surface is electrically contacted to a contact surface on the top side of the control element. If the contact surface is contacted by a finger, as a result, the signal generator signal applied thereto is changed. By means of the direct connection with the sensor surface, said signal change is retransmitted to the signal generator and can be evaluated.